package com.link.gateway.core.utils;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * <p>
 * RSA公钥/私钥/签名工具包
 * </p>
 * <p>
 * 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
 * </p>
 * <p>
 * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 * </p>
 *
 * @author IceWee
 * @version 1.0
 * @date 2012-4-26
 */
public class RSAUtils {

    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 124;

    /**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 256;

    /**
     * 生成密钥对(公钥和私钥)
     *
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(2048);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /**
     * 用私钥对信息生成数字签名
     *
     * @param data       已加密数据
     * @param privateKey 私钥(BASE64编码)
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return Base64Utils.encode(signature.sign());
    }

    /**
     * 校验数字签名
     *
     * @param data      已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @param sign      数字签名
     * @return
     * @throws Exception
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(Base64Utils.decode(sign));
    }

    /**
     * 私钥解密
     *
     * @param encryptedData 已加密数据
     * @param privateKey    私钥(BASE64编码)
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * @auther HuangLJ
     * @date 2018-12-26 21:15
     * @param
     * @return
     * @throws Exception 报错
     * @comments base64编码的密文解密
     */
    public static String decryptByPrivateKeyAndBase64(String encryptedDataBase64, String privateKey) throws Exception {
        byte[] encryptedData = Base64Utils.decode(encryptedDataBase64);
        return new String(decryptByPrivateKey(encryptedData, privateKey));
    }

    /**
     * 公钥解密
     *
     * @param encryptedData 已加密数据
     * @param publicKey     公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * 公钥加密
     *
     * @param data      源数据
     * @param publicKey 公钥(BASE64编码)
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }


    /**
     * 通过公钥获取加密字符串
     *
     * @author huanglongjian
     * @date 2019-08-22 10:35
     * @param base64Data 待加密字符串
     * @param publicKey 公钥
     * @return java.lang.String
     */
    public static String getBase64ByPublicKey(String base64Data, String publicKey) throws Exception {
        return Base64Utils.encode(encryptByPublicKey(base64Data.getBytes(), publicKey));
    }

    /**
     * <p>
     * 私钥加密
     * </p>
     *
     * @param data       源数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64Utils.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * 获取私钥
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return Base64Utils.encode(key.getEncoded());
    }

    /**
     * 获取公钥
     *
     * @param keyMap 密钥对
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return Base64Utils.encode(key.getEncoded());
    }


    public static void main(String[] args) throws Exception {
        String ss = RSAUtils.getBase64ByPublicKey("api-test|12451|" + System.currentTimeMillis() + "|6818",
                "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAmvVmbz3zuSTe9eEL8kL"
                        + "0wvYbFpmB81uE7kBoo+dqBw10pQ7Mzs26EcUgOkhzJVTyfjIEs+h5F3xOHu4I2QbgVo"
                        + "xDu2HdB917WbCtADOMY+kdNl1qETrsQ5YtcmRnJoj/W3W8EeAeSeAZeqFEybCbl8uUH"
                        + "SJSmRSYhIaLZ+BOGnpIR3Eg+UkeBMUZm5JAK4cDEmxd3UmL3rKwb+qkNYl08TjdEmA1"
                        + "MCmpGUnNv3UXOcZcAXc/frCd5tvC4JeSzE34Cxa+QEW1KWti1ZqCCaqFEyASyBCoW6M"
                        + "JWsrFc12AY8OvF8ycsmBwpkKdU8M1sXAIk2S84H6Qs9xmnJDus8m2VwIDAQAB");

        String sss = RSAUtils.decryptByPrivateKeyAndBase64(ss,
                "MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQCa9WZvPfO5JN714Qv"
                        + "yQvTC9hsWmYHzW4TuQGij52oHDXSlDszOzboRxSA6SHMlVPJ+MgSz6HkXfE4e7gjZBuBW"
                        + "jEO7Yd0H3XtZsK0AM4xj6R02XWoROuxDli1yZGcmiP9bdbwR4B5J4Bl6oUTJsJuXy5QdI"
                        + "lKZFJiEhotn4E4aekhHcSD5SR4ExRmbkkArhwMSbF3dSYvesrBv6qQ1iXTxON0SYDUwKa"
                        + "kZSc2/dRc5xlwBdz9+sJ3m28Lgl5LMTfgLFr5ARbUpa2LVmoIJqoUTIBLIEKhbowlaysV"
                        + "zXYBjw68XzJyyYHCmQp1TwzWxcAiTZLzgfpCz3GackO6zybZXAgMBAAECggEBAIDfJlnN"
                        + "xCxuJZ+Hkk/gr36U/uJEuHaT3nHmzx/BDcTfw+qh7GLxZZXxw2O1bU3W3/Vj09VruYl2r"
                        + "+G5RVJ5DYntDUeBlDk+UZ+996L7O/67mLfl6Jh70JJFC3bfWYoK1ZRSzh5vrcDyxz3dcT"
                        + "/ryPrtLDkumlMFdfKBkt7JBSuuyycSeBLkoTvLeVSRk7LvHycQCsvkn2UTEoWlcUSKVet"
                        + "YdZFGqcmb5LC41ci8wvSBQQWOnj9uv/pZeTAuG0GLuBV2+lSFmYc9NZREA+XtzBOAArGh"
                        + "W0fOQ57om3TFSk1gSCRnuq/F53yJuEVgEjB4v8E3L3O41aTgq7cfAWMF48ECgYEA0v24e"
                        + "9Zy6SghqTpm6umyBRCmyoxvprynX8jf3ZA0OFcrtik0gCnJi2cnSZN5bFBW3f7YrnVuqc"
                        + "IBvlK8wmCa7/Xu8rR6pw5oZ9rkQvyOXoXpxlEReOK2KhtSSCO3zWxSvPKrniJmrCofEif"
                        + "NODFjQ5J2RKJ2HxlLfGnEMea3dU0CgYEAvAO61BR1/pnrmM9wW4LS6nBSZg6ImrnfxGsc"
                        + "Gm3kf99PZJBJE5m4Ay8CSKUwVKu3nFbKIsyzUibpVPUTwxVH+Nvuy2EbqcHGwyK41pU8r"
                        + "mrjAL44bVDTRGnpKp7Qk6dk0hviz8iZRx9cJZwyTO6B2lZOsluHN1XZUctXppWmuDMCgY"
                        + "A9q9PEvsYPyJ8uK9fxSiWyvU9DXRE1l2cE5F4rEP9yiGhKcnjaDVzP1nLxWp3fPwxlDxy"
                        + "ewcx66i5AR0bNOhePlD8nygEf22JBGQYnXlLu5g2S3hdRUlMUs6+1TltnPAZjHDt1mXCR"
                        + "Wi6CzAd8KVNuaN0Q6rvEE0yxLOkf/OQa8QKBgFC/vVbmrsK5crE/rn7vEgz0Tr9cUJk7a"
                        + "XqfkgNb3T56N0v2mBwd8iUT5IQ0xiwnUAWKVOhbSEzpP19onqMzmaStOMMKounmuqoGWK"
                        + "J4mAZFC9e+2tdAVmxUnHrcmLJBu5Btv50EB6i/NEFG82eNLCIM3WHG460FZv+1OKDoNyF"
                        + "3AoGAaPIo2bUCzQjikW12xe1joAqdMp2Ccq35K/QNBuDoYtcYxxkmzm3ipVRxAhVT2SMF"
                        + "MJ6R9LMBTCUSFtpPdaFNHOxBH0FSUA+Klv2uHH0EquqnYODfsnaZo+Fd4haCU5M2piq5Q"
                        + "ias5K5b3hxiG4fCx5V3rVBd9alLOpy2XJAe96s=");
        String ss2 = "api-test|" + ss;
        ss2 = Base64Utils.encode(ss2.getBytes());
        System.out.println(ss2);
    }
}
